Manufacture of artificial silk



NOV. 30, 1937. Q G, JANSEN MANUFACTURE OF ARTIFICIAL SILK ZSheets-Sheet 1 Filed Oct. 9, 1936 3 m; I (bale/1b fizrzZ/amrm 1937. c. s. JANSEN 2,100,595

MANUFACTURE OF ARTIFICIAL SILK f Filed Oct. 9, 1956 2 Sheets-Sheet 2 Patented Nov. 30, 1937 iJNi'iED STATES MANUFACTURE OF ARTIFICIAL SILK Cornelis Gerrit Jansen, Arnhem, Netherlands, as-

signor to American Enka Corporation, Enka, N. 0., a corporation of Delaware Application October 9, 1936, Serial Nb. 104,888 In Germany October 31, 1935 6 Claims.

The present invention relates to the manufacture of artificial silk and more particularly to a device to be employed in the process of producing artificial threads and the like by the centrifugal method.

In the production of artificial silk according to the centrifugal method the thread after being spun and extruded through a coagulating medium is collected in a centrifuge or pot which is rotating at a relatively high speed. Due to the rotation of the pot a centrifugal force is created which acts to throw the thread against the inner wall thereof. After the spinning operation commences, concentric layers of yarn form within the pot to produce the so-called cake of yarn. In

order to control and maintain the deposition of the concentric layers, a reciprocating thread guide or spinning funnel is mounted for up and down movement within the center of the spinning pot.

During the period of forming one complete cake, the active radius of the pot gradually decreases. By active radius is meant the distance from the center of the pot and the last wound convolution of yarn. Accordingly, at the beginning of the spinning operation the active radius is the actual radius of the pot and upon the formation of a complete cake, the active radius has decreased to the radius of the thread free interior of the cake.

During the normal manufacture of artificial silk in which the thread is collected in a centrifugal pot, the thread guide funnel is reciprocated constantly, that is, the same number of strokes per minute are employed throughout the manufacture of one complete cake. Although the pot rotates several thousand times per minute, the convolutions of the thread itself are formed at a much lower rate. The number of convolutions depends upon and is determined by the rate of feed of the thread through the spinning funnel into the rotating pot.

In producing a cake which can be satisfactorily processed, it happens that a varying cross-wind ratio is maintained during one spinning opera.- tion. However, it has been determined through experience that the otherwise most favorable cross-wind ratios had the disadvantage that during one spinning operation, the cross-wind ratio remained substantially constant for a number of consecutive convolutions of the thread with the result that the convolutions are superimposed upon each other. In this portion of the cake the layers are too compact and harden to prevent satisfactory subsequent processing steps.

In order to more clearly understand the preceding paragraph the cross-wind ratio is hereafter explained in detail. If the rate of delivery of the thread into the pot from the lower end of the funnel is designated as X meters per minute and at a given instant during the spinning period the active diameter is D meters, then the active circumference of the inside of the cake is 7TB meters. If the rate of up and down strokes is N per minute, then the total travel of the funnel is equal to Nh meters per minute, h being the height of the pot. The number of convolutions of thread being fed into the pot per minute is equal to and the number of convolutions per full stroke of the funnel is equal to In view of the fact that the value of D is gradually changing as the diameter of the'c ake decreases, by the substitution of conventional figures, the resultant cross-wind ratio passes through such values as 5, 6 and 7 such values being known as simple cross-wind :ratios. this that the cross-wind ratio or the resultant value is the number of convolutions of thread fed into the spinning pot at a given moment during one full stroke of the spinning funnel (the up and down stroke).

During that period, or those periods when a' simple cross-wind ratio exists, a distinct diamond shaped pattern can be distinguished within the cake. Such a pattern is formed by the superim:

It can be seen from' position of several convolutions of thread. In.

addition to the foregoing disadvantages arising from the formation of these diamond shaped patgally spun cakes.

It is a further object of the present invention to provide a constantly'reciprocated thread guide funnel for use in the production of artificial silk, which funnel is formed in a manner to eliminate the necessity for and the resultant objections arising from the normal altering of the spinning machines to effect varying of. the stroke of the funnel. I

It is also contemplated to employ a novel1y.con structed spinning funnel which will effect a deposition of the thread within a rotating pot in such a manner as to prevent the formation of a pattern throughout all portions of an artificial silk cake. 7

Other objects and advantages will be apparent from the following detailed description when considered in connection with the accompanying drawings wherein:

Figure 1 is an elevational view of an improved thread guide funnel having a corrugated or notched mouth at the lower end from which the thread emerges;

Figure 2 is a bottom plan view of the funnel shown in Figure 1;

Figure 3 is a fragmentary view of a lower portion of a modified funnel;

Figure 4 exemplifies a lower portion of another modified form of thread guide funnel;

Figure 5 is a perspective view of the lower portion of a further modified form of funnel, and

Figure 6 is a side elevational view of the funnel illustrated in Figure 5, which funnel is shown in position within a conventional pot.

In referring to the drawings in detail, the numeral l indicates a thread guide funnel utilized in the manufacture of artificial silk according to the centrifugal process. At the lower end of this funnel the peripheral edge surrounding the mouth thereof is formed a series of projections 2 with resultant depressions therebetween.

The funnels indicated at l in Figures 1 to 4, inclusive, differ only in that the number of pro jections 2 are varied, i. 'e. in Figure l, eight projections are shown, in Figure 3 two projections are shown, while in Figure 4, four projections are shown. The projections and depressions may be in the form of symmetrical corrugations or, if desired, may be in the shape of saw-teeth 3 as exemplified in Figures 5 and 6. A pot 4 of the general type shown in Figure 6 is used in the op eration of any of the funnels specifically illustrated.

In applying the foregoing improved thread guide funnel to the present invention, it can readily be seen that when the funnel is reciprocated and freshly spun thread is fed therethrough, the thread emerging from the mouth is laid up by centrifugal force in the form of a plurality of convolutions to produce a cake. Ordinarily, if the mouth of the funnel were flat, then the thread would be deposited in a sloping unwavering convolution. The present construction, however, provides for depositing the thread on the inner wall of the spinning pot in a sinuous or undulating manner. The rotation of the pot causes the thread emerging from the mouth to ride over the un-dulated edge of the funnel and thereby imparts to the thread a wavy effect. This wavy deposition of the thread prevents a number of consecutive convolutions to superimpose upon each other during those periods in the formation of a complete cake when simple cross-wind ratios exist. Accordingly, the cake produced in practicing this invention is more permeable to treat-.- lng liquids, and also the unwinding thereof is enhanced. Although the undulations produced in the thread being collected overcome the foregoing disadvantages, they do not influence the characteristics of the finished thread such as the denier and dye affinity thereof.

Referring more particularly to Figures 5 and 6, it has been determined that the shape of the notches and the direction in which the thread runs with respect to this shape is of considerable importance. Whereas symmetrically shaped notches as shown in Figures 1 to 4, inclusive, can be used to considerable advantage, the notches such as 3 which conform to the shape of a sawtooth are particularly effective in producing an improved spun cake of artificial silk. As illustrated in connection with the notches of the funnels of Figures 1 to 4, inclusive, the saw-tooth type of projections may be similarly modified as to the number employed. These saw-teeth projections 3 must be shaped so that the downward sloping edges thereof are in the same direction as the rotation of the spinning pot.

It is to be understood that the scope of this invention is not to be restricted to the specific shape, size or number of notches or corrugations employed at the mouth of the spinning funnel, for while it has been found that best results are obtained where the funnel is provided with from two to eight projections, advantages may nevertheless be obtained by the use of more than eight projections.

What is claimed is:

l. A spinning funnel for use in the manufacture of artificial silk according to the centrifugal process comprising a hollow body portion having a series of projections and. depressions surrounding the mouth thereof over which the thread is caused to ride as it emerges and is laid up to form a cake within a pot.

2. A spinning funnel for use in the manufacture of artificial silk according to the centrifugal process comprising a hollow body portion having a series of projections conforming to the type of saw-teeth surrounding the mouth thereof over which the thread is caused to ride as it emerges and is laid up to form a cake within a pot, the said saw-teeth projections having edges sloping downwardly in the same direction as the rotation of the pot.

3. A spinning funnel for use in the manufacture of artificial silk according to the centrifugal process comprising a hollow body portion having from two to eight projections and a corresponding number of depressions surrounding the mouth thereof over which the thread is caused to ride as it emerges and is laid up to form a cake within a pot. J

4. A spinning funnel for use in the manufacture of artificial silk according to the centrifugal process comprising a hollow body portion having from two to eight saw-teeth projections surrounding the mouth thereof over which the thread is caused to ride as it emerges and is laid up to form a cake within a pot, the said sawteeth projections having edges sloping downwardly in the same direction as the rotation of the pot.

5. A spinning funnel for use in the manufacture of artificial silk according to the centrifugal process comprising a hollow body portion having at least two projections and at least two depressions surrounding the mouth thereof over which the thread is caused toride as it emerges and is laid up to form a. cake within a pot.

6. A spinning funnel for use in the manufacture of artificial silk according to the centrifugal process comprising a hollow body portion having at least two saw-teeth projections surrounding the mouth thereof over which the thread is caused to ride as it emerges'and is laid up to form a cake within a pot, the said saw-teeth projections having edges sloping downwardly in the same direction as the rotation of the pot.

CORNELIS GERRIT JANSEN. 

